Ed Miliband is so firmly established as the underdog in these weekly bouts that anyone with an ounce of sporting spirit must wish he could occasionally land a punch on the prime ministerial jaw. What goes through the Leader of the Opposition’s mind as he prepares for these contests? Week after week, he chooses subjects on which he is unlikely to be defeated: this week the NHS.

But this defensive mentality means that again and again, he avoids talking about the economy. He cedes this commanding territory to his adversary. The longer he does so, the more tentative he sounds. This week, he should have been able to point up the embarrassing contrast between the brave plans announced in 2010 to deal with the deficit within a single Parliament, and the almost unimaginably large amounts which are still being borrowed.

Labour faces an awkward problem as it goes in to the 2015 election: it can hardly promise, with credibility, to borrow more than is already being borrowed. It has, in a sense, been left with nowhere to go, which is why it is keeping so quiet. But the Labour leader should still be able to make the argument that the present Government, far from being prudent and responsible, has been recklessly spendthrift: has allowed politics to trump economics, and is borrowing up to the hilt in a desperate bid to get itself re-elected. Oltep (“Our Long-Term Economic Plan”) might more accurately be described as a short-term political gamble.

Cameron would have all sorts of retort to that. He would wax eloquent on the dreadful mess left behind by Gordon Brown, and by Brown’s advisers, who included Ed Balls and Miliband himself. He would go on and on about the number of jobs being created, and would claim that the deficit will be dealt with in the next Parliament.

But Cameron is not even being forced to defend himself. Miliband leaves him in command of the field. No wonder the Labour benches watch their leader with unease. He appears not to be leading but to be waiting for something to turn up.